Fire detection and suppression system for use in a decompression chamber

ABSTRACT

A fire detection and suppression system for recompression and decompression chambers comprising a plurality of optical detectors, a plurality of fog nozzles connected to a water storage tank which is under gas pressure of an inert gas, such as helium. The presence of fire in a recompression and/or decompression chamber actuates the optical sensors or detectors of the system which in turn emit water under gas pressure into the recompression and/or decompression chamber.

United States Patent 1 1 McMahon Sept. 9, 1973 [5 FIRE DETECTION AND SUPPRESSION 2,570,280 10/1951 Roffman 169/2 R SYSTEM FOR USE IN A DECOMPRESSION 3,592,269 7/1971 Stults l el al 3,713,491 1 1973 Grabowski et al. 169/2 R irimq' 4 "F!-fB9b FE,Y q; Attorney-R. S. Sciascia and Charles D. B. Curry [5 7 ABSTRACT A fire detection and suppression system for recompression and decompression chambers comprising a plurality of optical detectors, a plurality of fog nozzles connected to a water storage tank which is under gas pressure of an inert gas, such as helium. The presence of tire in a recompression and/or decompression chamber actuates the optical sensors or detectors of the system which in turn emit water under gas pressure into the recompression and/or decompression chamber.

10 Claims, 1 Drawing Figure [75] Inventor: Kenneth C. McMahon, San Jose,

Calif.

[7 3] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

[22] Filed: July 20, 1972 [21] Appl. No.: 273,563

[52] US. Cl. 169/2 R, 169/9 [51] Int. Cl A624: 3/00, A62c 35/18 [58] Field of Search 169/2 R, 5, 9

[56] References Cited UNITED STATES PATENTS 517,394 3/1894 Prosser l69/9 :Di- E :DI- E E 31 s P4 WATER FIRE DETECTION AND SUPPRESSION SYSTEM FOR USE IN A DECOMPRESSION CHAMBER BACKGROUND OF THE INVENTION 1. Field of the Invention The subject matter of the present invention realtes generally to a fire detection and suppression system and more particularly to a fire detection and suppression system which operates in a recompression and/or decompression chamber environment.

2. Description of the Prior Art Generally, prior fire detection systems did not provide protection in a recompression and/or decompression environment. Moreover, the prior systems were slow in response. The prior systems also used very unstable and toxic gases which for biological reasons would be extreme hazards for life support systems, such as hyperbaric recompression and/or decompression chambers.

SUMMARY OF THE INVENTION Briefly, the present invention is a fire detection and suppression system for recompression and/r decompression chambers comprising a plurality of optical detectors, a plurality of fog nozzles connected to a water storage tank which is under gas pressure of an inert gas, such as helium. The presence of fire in the recompres sion and/or decompression chamber actuates the optical sensors or detectors of the system which in turn emit water under gas pressure into the recompression and/or decompression chamber.

Simultaneously with thc-detonating of the squib valve the amplified signal from the detectors will actuate a time-delay switch which shuts off a solenoid valve after a preselected time, thereby stopping the flow of helium to the water tank. This system has been found to overcome the aforementioned problems of the prior fire detection systems.

The unique fire detection system, which is the subject matter of the present invention, has been found to be particularly useful in the recompression and/or decompression chamber of the Mark I Deep Diving System, currently being used by the United States Navy for deep water research and salvage.

STATEMENTS OF THE OBJECTS OF INVENTION It is a primary object of the present invention to provide a fire detector and suppression system which can be used in shipboard recompression and/or decompression chambers.

Another object of the present invention is to provide a fire detection and suppression system with rapid response in a recompression and/or decompression environment.

Another object of the present invention is to provide an essentially hazard-free fire suppression system which will operate in a recompression and/or decompression environment.

Other objects and features will be apparent from the following description of the invention and from the accompanying drawing in which the sole figure is a schematic diagram of the preferred embodiment of the present invention.

Referring to the drawing, in order to protect divers against the hazard of a fire, a fire detecting and suppression system 11 is integrated into the walls of a deck recompression and/or decompression chamber 13. The system 11 includes a plurality of optical detectors l5 and a plurality of fog nozzles 17 which are both located in chamber 13. It has been found that six detectors provide adequate coverage. However, it is to be understood that a greater or lesser number of detectors and- /or nozzles may be used depending upon the particular need. The fog nozzles 17 provide a water fog which is used to suppress the fire after the fire is detected by optical detectors 15. The fog nozzles 17 are the standard fog laying type or their equivalent. The optical detectors l5 detect a fire by sensing the increased ratio of infrared (infrared-ultraviolet balanced ambient) light present due to fire. Any one or all of detectors 15 generate an output signal(s) V when a fire is located in the sensing range of any one or all of detectors 15. Detectors 15 should be appropriately located within chamber 13 to provide the widest range of coverage. This method of detecting is preferred over a normal or smoke system because of its rapid response and compatibility with the high pressure environment. Water is preferred as the suppressor medium because of the potential toxicity of the alternative fire suppression compounds which are available.

Any one of the detectors 15 can operate the system 11. The individual output signal(s) V from detectors 15, alone or collectively, will detonate the squib valve 19. With switch 33 in the closed or actuated position a fire will be detected by any or all the detectors 15. The low power sensing signal V from one or several detectors 15, is amplified by amplifier 31. The amplified signal V from amplifier 31, is applied to the input of a detonating device located in squib valve 19. This causes squib valve 19 to open allowing the water from tank 21,-which is under helium pressure and is maintained at psig over chamber 13 pressure, to flow to the fog nozzles 17. Simultaneously with the activation of squib valve 19, the applied signal V is applied to activate the alarm light 39 located on a control console on the decompression chamber 13. The amplified signal V is then applied to the input of time-delay switch 37. Time-delay switch 37 is present to close a normally open solenoid valve 25 when the water in tank 21 has been expelled into chamber 13. The system 11 is powered by power supply 35 which may be any power supply well known in the art. This reference pressure function is achieved by use of chamber pressure reference line 23 which is connected to pressure regulator 27 and tank 21 pressure reference line 27a which regulates the pressure of the helium to water tank 21. The normally open solenoid 25 allows helium to flow into water tank 21 to keep the water under a constant pressure of 100 psi above chamber 13 pressure. The actuated solenoid valve 25 turns off the helium flow from helium tank 29 in order to prevent helium from entering the chamber when the water supply from water tank 21 is depleted. The flow of helium from storage tank 29 is regulated by regulator 27. Solenoid valve 25 is normally open to keep a constant pressure of 100 psi above chamber 13 pressure on the water tank 21. The emergency override switch 32 is located at the operators station and connected directly to power supply 35 to permit direct actuation of valve 19. This can be used to manually activate the system if a fault occurred in the detection system.

The recompression and/or decompression chamber 13 and the fire detector system 11 may contain additional backup and fail-safe components. For example, whenever there is a gas or liquid hull penetration in chamber 13 a quick-acting ball valve may be used for an emergency shut-off in case of a system 11 failure. The squib valve 19 can be backed up by a second squib valve in parallel and a third manually operated valve 19a. This type of configuration is well known in the art.

The system 1 1 has been found to operate successfully and rapidly. For example, the system 11 was tested in a helium atmosphere. It was found that water emerged from nozzles 17 within approximately 50 milliseconds after an infra red signal was applied to detectors 15.

What is claimed is:

l. A fire detection and suppression system for use in a chamber comprising in combination:

a. at least one fire sensing means located in said chamber;

b. at least one dispensing means for dispensing a fire suppression material, said dispensing means being located in said chamber;

c. a storage means for containing a fire suppression material;

(1. a means for transferring the flow of said fire suppression material from said storage means to said dispensing means;

e. a pressure means for applying a pressure to said fire suppression material;

f. a means for activating the flow of said fire suppression material to said dispensing means; and

g. a means to deactivate said pressure means when said fire suppression material is depleted.

2. A fire detection and suppression for use in a variable pressure chamber comprising in combination:

a. a fire sensing means located in said chamber;

b. a fire dispensing means for dispensing a fire suppression material in said chamber;

c. a storage means for containing a fire suppression material;

d. a means for transferring the flow of said fire suppression material from said storage means to said dispensing means at a constant pressure above the reference pressure of said chamber;

e. a pressure means for applying a pressure to said fire suppression material;

f. a means for activating the flow of said fire suppression material to said dispensing means; and

g. a means to deactive said pressure means when said fire suppression material is depleted.

3. The device recited in claim 2, said means for transferring the flow of said fire suppression material further comprises a chamber pressure reference means operatively connected to said chamber, said storage means and said pressure means to regulate and control the pressure to said pressure means where said reference means keeps said fire suppression material under a constant pressure above the chamber pressure.

4. The device recited in claim 1 wherein said fire sensing means is a plurality of fire sensing means.

5. The device recited in claim 1 wherein said at least one dispensing means is a plurality of dispensing means for dispensing a fine spray of vapor of said fire suppressing material.

6. The device recited in claim 5 wherein said fire suppression material is water under pressure from an inert gas.

7. The device recited in claim 4 wherein said inert gas is helium.

8. The device recited in claim 1 wherein said pressure applying means is a helium tank with a pressure regulator.

9. The device recited in claim 1 wherein said means to deactivate said pressure means is a solenoid valve actuated by a time delay circuit connected between said storage means and said pressure applying means, said time delay circuit being preset to activate and open said solenoid valve when said fire suppression material is depleted.

10. The device recited in claim 1 wherein said means for activating the flow of said fire suppression material is a rapid response valve located between said dispensing means and said storage means and is activated from a fire signal from said fire sensing means.

I i i i 

1. A fire detection and suppression system for use in a chamber comprising in combination: a. at least one fire sensing means located in said chamber; b. at least one dispensing means for dispensing a fire suppression material, said dispensing means being located in said chamber; c. a storage means for containing a fire suppression material; d. a means for transferring the flow of said fire suppression material from said storage means to said dispensing means; e. a pressure means for applying a pressure to said fire suppression material; f. a means for activating the flow of said fire suppression material to said dispensing means; and g. a means to deactivate said pressure means when said fire suppression material is depleted.
 2. A fire detection and suppression for use in a variable pressure chamber comprising in combination: a. a fire sensing means located in said chamber; b. a fire dispensing means for dispensing a fire suppression material in said chamber; c. a storage means for containing a fire suppression material; d. a means for transferring the flow of said fire suppression material from said storage means to said dispensing means at a constant pressure above the reference pressure of said chamber; e. a pressure means for applying a pressure to said fire suppression material; f. a means for activating the flow of said fire suppression material to said dispensing means; and g. a means to deactive said pressure means when said fire suppression material is depleted.
 3. The device recited in claim 2, said means for transferring the flow of said fire suppression material further comprises a chamber pressure reference means operatively connected to said chamber, said storage means and said pressure means to regulate and control the pressure to said pressure means where said reference means keeps said fire suppression material under a constant pressure above the chamber pressure.
 4. The device recited in claim 1 wherein said fire sensing means is a plurality of fire sensing means.
 5. The device recited in claim 1 wherein said at least one dispensing means is a plurality of dispensing means for dispensing a fine spray of vapor of said fire suppressing material.
 6. The device recited in claim 5 wherein said fire suppression material is water under pressure from an inert gas.
 7. The device recited in claim 4 wherein said inert gas is helium.
 8. The device recited in claim 1 wherein said pressure applying means is a helium tank with a pressure regulator.
 9. The device recited in claim 1 wherein said means to deactivate said pressure means is a solenoid valve actuated by a time delay circuit connected between said storage means and said pressure applying means, said time delay circuit being preset to activate and open said solenoid valve when said fire suppression material is depleted.
 10. The device recited in claim 1 wherein said means for activating the flow of said fire suppression material is a rapid response valve located between said dispensing means and said storage means and is activated from a fire signal from said fire sensing means. 